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<html lang="zh">
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	<meta charset="UTF-8">
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	<title>Document</title>
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<body>
	<script>
		//min ≤ r ≤ max
		function RandomNumBoth(Min,Max){
      var Range = Max - Min;
      var Rand = Math.random();
      var num = Min + Math.round(Rand * Range); //四舍五入
      return num;
		}
		//min ≤ r < max
		function RandomNum(Min, Max) {
      var Range = Max - Min;
      var Rand = Math.random();
      var num = Min + Math.floor(Rand * Range);  //舍去
      return num;
		}
		//min < r ≤ max
		function RandomNum(Min, Max) {
      var Range = Max - Min;
      var Rand = Math.random();
      if(Math.round(Rand * Range)==0){             
          return Min + 1;
      }
      var num = Min + Math.round(Rand * Range);
      return num;
		}
		//min < r < max     
		function RandomNum(Min, Max) {
      var Range = Max - Min;
      var Rand = Math.random();
      if(Math.round(Rand * Range)==0){
          return Min + 1;
      }else if(Math.round(Rand * Max)==Max)
      {
          index++;
          return Max - 1;
      }else{
          var num = Min + Math.round(Rand * Range) - 1;
          return num;
      }
 		}
	</script>
</body>
</html>